Subramanian Subbaya, Mishra Rakesh K, Singh Lalji
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
Bioinformatics. 2003 Apr 12;19(6):681-5. doi: 10.1093/bioinformatics/btg067.
Bkm (Banded krait minor) satellite DNA sequences (GATA repeats) have been shown to be associated with the sex determining chromosomes of various eukaryotes and have been implicated in the evolution and differentiation of sex chromosomes in snakes. The objective of the study is to analyze the GATA repeats of human genome specifically, the Y-chromosome, and other model organisms to understand the possible function and potential role in higher order chromatin organization.
Our extensive analysis of GATA repeats in the prokaryotic and eukaryotic genomes, which have been completely sequenced so far, has revealed that GATA repeats are absent in prokaryotes and have been gradually accumulated in higher organisms during the course of evolution. In human, the Y-chromosome has the highest GATA repeat density, which predominantly exists in the Yq centromeric region. Generally, occurrence of repeats in the genomes decreases steadily as the length of the repeat increases. In contrast, we report, that the occurrence of GATA repeats increases as the length of the repeat increases from six tandem repeats onwards and peaks at (GATA)(10-12). This has not been observed with any other simple repeat. Distribution of (GATA)(10-12) along the chromosome and their close proximity to Matrix Associated Regions (GATA-MAR) suggests that it may be demarking chromatin domains for a coordinated expression of genes residing in these domains.
已证明Bkm（小斑海蛇）卫星DNA序列（GATA重复序列）与各种真核生物的性别决定染色体相关，并与蛇类性染色体的进化和分化有关。本研究的目的是专门分析人类基因组，特别是Y染色体以及其他模式生物的GATA重复序列，以了解其在高级染色质组织中的可能功能和潜在作用。
我们对目前已完成全序列测序的原核生物和真核生物基因组中的GATA重复序列进行了广泛分析，结果显示原核生物中不存在GATA重复序列，且在进化过程中其在高等生物中逐渐积累。在人类中，Y染色体的GATA重复序列密度最高，主要存在于Yq着丝粒区域。一般来说，随着重复序列长度的增加，基因组中重复序列的出现频率会稳步下降。然而，我们发现，从六个串联重复序列开始，GATA重复序列的出现频率随着重复序列长度的增加而增加，并在（GATA）（10 - 12）时达到峰值。这在其他任何简单重复序列中都未观察到。（GATA）（10 - 12）沿染色体的分布及其与基质相关区域（GATA - MAR）的紧密接近表明，它可能在界定染色质结构域，以便协调这些结构域中基因的表达。
